Criteria for factor identification in factor analysis according to J. Algina (1980) are summarized, and a procedure is presented to determine rotationally underidentified factors by adding restrictors and to carry out the rotation for old and new restrictions and in latent path analysis. Two illustrations are presented. (SLD)

An error in an essential equation within the article by Williams and Zimmerman is corrected, and the algebraic inequalities are translated into questions a researcher can ask about simple or residualized difference scores. Williams and Zimmerman acknowledge the error and note that main conclusions are not affected. (SLD)

Reports on the validity of the Multiple Poisson (nP) model of word distribution in full-text document collections. A practical algorithm for determining whether a certain word is distributed according to an nP distribution and the results of a test of this algorithm in three different document collections are described. (14 references) (KRN)

An algorithm based on the majorization theory of J. de Leeuw and W. J. Heiser is presented for fitting the slide-vector model. It views the model as a constrained version of the unfolding model. A three-way variant is proposed, and two examples from market structure analysis are presented. (SLD)

How item bias indexes based on item response theory (IRT) identify bias that results from multidimensionality is demonstrated. Simulation results suggest that IRT-based bias indexes detect multidimensional items with bias but do not detect multidimensional items without bias. They also do not confound between-group differences on the primary test.…

Within the multivariate normality framework, a formula is provided for computation of the criterion-related validity of composite scores based on the highest (or lowest) of several equivalent measures. This partial composite score has more validity than each single observation, but less validity than a composite based on all observations. (SLD)

Reasons/methods for standardizing discriminant function coefficients are reviewed, and use of the pooled within-groups variance estimate is examined. Use of total or pooled within-groups estimates can be justified only on purely mathematical grounds. Total variance estimates offer a more consistent and parsimonious approach than do pooled…

Applications of the confirmatory factor analysis block-diagonal model to published data on 18 multitrait-multimethod matrices were reviewed to show widespread estimation problems. Possible causes of estimation difficulties were explored using computer simulations. These problems make the block-diagonal approach less useful than has generally been…

A model for the age standardization of test scores is presented, which is fitted to the percentile points of the raw score distribution and assumes a linear trend of each percentile with age. The model's applications in standardizing tests and diagnostic plots produced by a computer program--STANEW--are described. (SLD)

This paper proposes a generalization of Thurstonian probabilistic choice models for analyzing both multiple preference responses and their relationships. The approach is illustrated by modeling data from two multivariate preference experiments. Preliminary data analyses show that the extension can yield an adequate representation of multivariate…

A new procedure is proposed for handling nominal variables in the analysis of variables of mixed measurement levels, and a procedure is developed for handling ordinal variables. Using these procedures, a monotonically convergent algorithm is constructed for the FACTALS method for any mixture of variables. (SLD)

A general model for two-level multivariate data, with responses possibly missing at random, is described. The model combines regressions on fixed explanatory variables with structured residual covariance matrices. The likelihood function is reduced to a form enabling computational methods for estimating the model to be devised. (Author)

How syntax affects sentence prosody is explored. It is demonstrated that the lengthening of phase-final words and pausing afterward reflect a distinctly prosodic representation in which phonological constituents are arranged in a hierarchical nonrecursive structure. A model of prosodic pronunciation is also presented. (SLD)

Discusses a classroom-teaching example provided in this issue. Comments that teachers, using curricular materials and activities, adapt, elaborate on, or invent the context of learning in ways that ensure that students study important central concepts in science and mathematics, and that the understandings students develop are accurate and rich.…

Considers some changes that the use of graphics calculators impose on the assessment of calculus and mathematical modeling at the undergraduate level. Suggests some of the ways in which the assessment of mathematical tasks can be modified as the mechanics of calculation become routine and questions of analysis and interpretation assume greater…